Calorimetric method and apparatus adapted for gas mixing control



y 1935- E. x. SCHMIDT 2,002,279

CALORIMETRIQ METHOD AND APPARATUS ADAPTED FOR GAS MIXING CONTROL FiledMay 29, 1951 2 Sheets-Sheet 1 May 21, 1935. E. x. SCHMIDT CALORIMETRIQMETHOD AND APPARATUS ADAPTED FOR GAS MIXING CONTROL Filed May 29, 1931 2Sheets-Sheet 2 JnvenZo 7. form X 50/44/07- 5] ZMM/W y Patented May 21,1935 UNITED STATES PATENT OFFICE CALORIMETRIC METHOD AND APPARATUSADAPTED FOR GAS MIXING CONTROL Edwin X. Schmidt, Whitefish Bay, Wis.,assignor to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation ofDelaware Application May 29, 1931, Serial No. 540,863 9 Claims. (01.48180) This invention relates to improvements in 0211- conduit lcomprises propane gas, or other gas orimetric methods and apparatus, andwhile of relatively high quality or total heating value not limitedthereto the invention relates more per unit volume, with which it isdesired to mix particularly to calorimetric methods of and ap the air orother gaseous fluid of relatively low paratus for proportioning gaseousfluids. quality or total heating value per unit volume 5 An object ofthe invention is to provide novel flowing through conduit II, for thepurpose of calorimetric methods of quickly regulating and providin a flwin mix r of gaseous fluids in accurately controlling the relativeproportionalconduit I2 having the desired or required quality of aplurality of flows of gaseous fluids to ity or total heating value perunit volume.

provide a.fiowing mixture of substantially con- Thus it may be assumedthat the fluid in con- 0 stant quality or total heating value per unitduit I 0 is subject to variations both in its rate volume. of flow(which variations may be due to varia- Another object is to providenovel methods, tions in the demand for or rate of flow of the incalorimetry, of compensating for the efiects mixture in conduit l2 or tovariations in the rate of variation in ambient temperature. f generationor pp y f aid fluid in onduit 15 Another object is to provide novelforms of gas ID) and in the qual ty or t tal heatin ue mixing controlsystems for carrying out the p r U q a of Such fi It iS e o eaforementioned methods. necessary to provide some means for automati-Another object is to provide an electrically Cally controlling the rateof fl w of luid throu h operated gas mixing control system which funco dII in Order that the quality t l tions automatically under allconditions after h at n al e p un t Volume of the mixture of manualinitiation of operation thereof. as s n C uit S a l be m i ained ub tan-Another object is to provide'novel means for tiallyconstant. maintaininga given volumetric proportionality AS Wi be app the degree to which theof the constituent gaseous fluid flows in the event quality o al eati gvalue D unit Volume of failure of certain elements of the control sys-0f the mi ture of fluids in conduit l2 remains tem. constant dependsprimarily upon the rapidity of Another object is to provide novel formsof sigchange or variation in the rate of flow of fluid naling elementsto function automatically unin conduit II in response to such variationsin der the conditions last mentioned. quality of the mixture in conduit[2, if it ,be as- 30 Other objects and advantages of the invention sumedthat the quality of the mixture isconwill hereinafter appear. tinuouslyand accurately determined. It is there- 'I'he accompanying drawingsillustrate certain fore a primary object of my invention to provideembodiments of the invention which will now he means whereby the rate offlow of fluid in conduit described, it being understood that theinvention H is changed very quickly in response to any. 35

is susceptible of embodiment in other forms withvariations in quality ofthe mixture of fluids in out departing from the scope of the appendedconduit l2, without sacrificing the substantial declaims. gree ofaccuracy of the determinations of quality In the drawings, Figure 1 is aschematic and of the aforementioned mixture.

40 diagrammatic illustration of a gaseous fluid mix- Accordingly, Iprovide means for continuously 40 ing control system constructed inaccordance with withdrawing through conduit I3 a volumetricallymyinvention. 1 constant sample of the mixture of fluids flowing Fig. 2 isa detail vertical sectional view of a in nduit [2, said means comprisesa positive part of the calorimetric device shown, in Fig. displacementpump 14 of well known form which I l, and operates within and is sealedby a body of liquid I5, 45

Fig. 8 s a schematic and diagrammatic u such as water, within a tank I6.The intake of tration of a modified form of gaseous fluid mixpump I4 isrepresented by the conduit I1 shown ing control system constructed inaccordance with in dotted lines and the outlet thereof is repremyinvention. I sented by the conduit IR shown in dotted lines. I

Refe o the d aw ngs, the numerals I 0 Conduit leads to the preliminarymixing cham- 50- and II designate conduits through which two ber l9 0!the calorimeter burner 20, said burner fluids of diiferent quality ortotal heating'value having a tube or tip 2| extending upwardly per unitvolume are adapted to flow from any through a secondary air chamber 22and through suitable sources, respectively. For example, it the bottomof a pair of laterally perforated cups 5 may be assumed that the fluidflowing through 23 and 24 which are rotatably adjustable relaof primaryair and gas within chamber l9, and

"the latter-communicating with the chamber 22 to provide a supply ofsecondary air to the burner. As shown the pumps l4 and 25- are driven atlike speeds by means of a suitable constant speed motor 29 throughsuitable gearing 30, 3|. The

- amounts of gas and air supplied by pumps l4 and 25, respectively, willtherefore be proportioned in accordance with the relative capacities ofsaid pumps. The topportion of' tank It is vented sumciently to providefor atmospheric pressure of the air above the level' l of the liquid,such air being drawn into pump 25 at the left-hand side of the latter ina well known manner.

Suitable means are also preferably provided for supplying the gas sampleto pump l4 at substantially atmospheric pressure; said means comprisingan orifice plate 32 and a vent to atmosphere which preferably is in theform .of a burner 33. This burner is shown more in detail in Fig. 2

as' consisting of a tube or tip 33 having inlets 33 at the lower endthereof for primary combustion air and having lateral kerfs or slits 33adjacent to the upper end thereof for emission of the combustible gas. Atube or jacket 33 surrounds the burner tip to protect the flame fromdrafts, said jacket having openings 33 therein to provide a sulficiencyof secondary combustion air for the combustible mixture in the burnerwhen ignited.

,It will be apparent that due to intimate contact of the gas and airwith the body of liquid l5 at substantially atmospheric pressure, saidfluids are metered and proportioned under like conditions oftemperature, pressure and saturation.

Suitable piping 34 may be provided for draining by gravity the condensedmoisture formed in the gas and air conduits and in other parts of thecalorimeter; a branch pipe 34 being provided for initial admission of aquantity of water or similar liquid to provide a seal, and a secondbranch pipe 34 being provided to intermittently siphon off the excessliquid of the seal. Any well known means may be provided forreplenishing the-liquid in tank I6 to maintain the body l5 thereof atthe level I5 I The means responsive to variations in quality or totalheating value per unit quantity of the gas sample comprises essentiallya galvanometer system including the usual permanent magnet 35, coil 36,and needle 31 which isbiased to a normal or zero position as by means ofthe hairspring 38. Needle 31 is adapted to be moved from and toward thenormal position thereof in accordance with the value of the E. M. F.generated in the circuit of coil 35. Included in such circuit are hotandcold-junctions 39 and '48 of a thermo-couple; the hot-junction 39 of thethermocouple beingexposed in the burner 20 to the calorific ortemperature effect of combustion of the continuous sample of gas in thepresence of a proportioned quantity of air, as aforedescribed, and thecold-junction 40 of the thermo-couple being spbjected to a differenttemperature, which is preferably the temperature of the liquid I5 intank 16.

The hotand cold-junctions are connected in series with each other intheusual manner, and as is well known each junction consists of twodifferent metals. For example, wires 4| and 42 formed of iron may bejoined as by welding, brazing or the like to the opposite ends of acommon wire 43 formed of constantan, which is an alloymixture flowing inconduit I2 may be preselected.

Movement of table 45 and pointer 41 may be effeoted in anydesiredmanner, but I prefer to employ a split field reversible motor'thearmature of which is indicated at 48 and the respective fields of whichare indicated at 49 and 58. Connection of armature 48 across suitableenergy supply lines L L3 through series field 50 for operation thereofin one direction is controlled by a manually operable push button switch58 and connection of said armature across said lines through seriesfield 49 for operation thereof in the reverse direction is controlled bya similar switch 49.

Motor 48 is adapted through worm gear 5| and pinion 52 to drive a shaft53 to which table 45 is non-rotatably keyed, as indicated at 54,-thearrangement being such that table 45 may be reciprocated longitudinallyof shaft 53. The means for eifecting longitudinal reciprocation of table45 is shown more or less diagrammatically as comprising a tubularextension '55 having a lug 56 engaged by an eccentric or cam 51 which isoperable through shaft 58 and gearing 59 by a -motor 50 which may beconnected to lines L L or to any other suitable source of energy supplyfor operation thereof at a predetermined constant speed. It may beassumed, for example, that cam 51 is so shaped and that motor 68 isoperated at such a speed as to provide for raising table 45 to its upperextreme position once in every seven and one-half seconds.

Also connected to shaft 58 is a pair of cams I GI and 52 which areangularly adjustable relatively to each other. Cams BI and 62 have highand low portions as shown which are adapted to engage suitable abutmentsor projections 63- and 84* upon a pair of contact carrying arms 83 and64,--the contact points being shown at 53 and 64'. as to effectengagement of contact points 63 64 upon each movement of table 45 to itsupper extreme position,-it being noted that said cams GI and 52 arecapable of adjustment in a manner to vary the period of time duringwhich said contact points 53, t4 remain closed.

A second pair of cams 65 and 66 is carried by shaft 81, said cams beinglikewise adjustable with respect to each other and said shaft beingdriven through suitable gearing 68 and 59 from shaft 58 at apredetermined faster speed than the latter. For example,the speed ofshaft 51 is preferably such that the cams 65 and 86 control arms 18 and1| in a manner to provide for engagement of the contact points 10 and 1|carried thereby once during each period of six seconds. It will beapparent that with the adjustments aforede scribed the arrangement issuch that the contact points 63, 64 and 1ll 1l of the interrupterswitches are closed simultaneously once during Cams 6| and 62 arepreferably so adjusted each period of thirty seconds, at which time thetable 45 will likewise be in its supper extreme position.

Here it may be pointed out that table 45 carries two double-actingswitch mechanisms 12 and 13, and the switch 12 is provided with a pairof normally closed auxiliary contacts 12, 12 which when opened areadapted to render said switch ineifeotive. The oscillatable contactor 12of switch 12 is movable into engagement with sta tionary contact 12through engagement of an element 12 with the part 31 of the galvanometerneedle upon upward movement of table 45, and said contactor 12 ismovable into engagement with stationary contact 12 through engagement ofan element 12 with said part 31 upon upward movement of the table,depending of course upon the relative position of the galvanometerneedle.- On the other hand, if part 31 of the needle is directly abovethe element 11" upon upward movement of table 45 contact 12 carried bysaid element will be moved out of engagement with contact 12 to disableswitch 12. Hence if the contacts 63*, 64 and 1| of the interrupterswitches happen to be closed at that instant the circuit through saidinterrupter contacts will be incomplete due to opening of said auxiliarycontacts 12, 12 of switch 12.

The oscillatable contactor 13 is adapted to be engaged with the contact13 when needle 31 is positioned at the right hand side of switch 13 asshown in the drawing,s uch engagement being effected by engagement of anelement 13 with part 31 of the galvanometer needle upon upward-movementof table 45. In the event of extinguishment of the burner flame from anycause, or upon failure of the thermo-couple circuit such as to result indeenergization of coil 35, the needle 31 will move under the bias ofspring 38 toward its left-hand position, and upon raising of table 45the contactor 13 is tilted into engagement with contact 13 by engagementof an element 13 with the part 31* of the needle 31.

The means for controlling the volumetric rate of flow of fluid throughconduit I I comprises a valve of suitable form located at the point 14,said valve being operable in reverse directions selectively through themedium of gearing 15 and a split-field reversible motor, the armature ofwhich is indicated at 16 and the fields of which are indicated at 11 and18. Energization of field 11 to cause operation of motor 15 in adirection to effect closing movement of valve 14 results from closure ofa normally open electromagnetic'ally operable switch 18, energization ofthe operating winding of the latter switch being dependent uponsimultaneous closure of contacts 12 12 and 12 12 of switch 12 andcontacts 63 64 and 10 1! of the interrupter switches. Energization offield 18 to cause operation of motor 16 in the reverse direction toeffect opening movement of valve 14 results from closure of a similarnormally open electromagnetically operable switch 80, energization ofthe operating winding of the latter switch being dependent uponsimultaneous closure of contacts 12, 12 and 12 12 of switch 12 andcontacts 53 54 and 10 1| of the interrupter switches.

More particularly, if it be assumed that the quality or heating valueper unit volume of the mixture of fluids flowing in conduit I! has risenabove the value preselected therefor by the adjustment of table 45 asindicated by the position of pointer 41, the part 31 of needle 31 willhave been moved toward the right to overlie the element 12 of switch12,due to the increased value of the electromotive force generated inthe circuit of coil 35 by the richer quality of the gas sample burned inthe presence of the hot-junction 38 of the thermo-couple.

Therefore when table 45 is lifted by the means aforedescribed element 12will be engaged by part 31 of the needle to effect tilting of contactor12 into engagement with contact 12 Thereafter within a maximum period ofthirty seconds the contacts of both interrupter switches will besimultaneously closed, and, assuming prior closure of a manuallyoperable push-button switch B, an energizing circuit for the winding ofswitch 80 will be completed. Said circuit may be traced from line L byconductor 8| through switch B, conductor ,82 through contacts 63, 64 ofone of the interrupter switches, conductor 83 to and through contactor13 and contact 13 of. switch 13, conductor 84 through contacts 10 11 ofthe other interrupter, conductor 85 to and through auxiliary contacts12, 12, contactor 12 and contact 12 of switch 12, conductor 88 to andthrough the winding of switch 80, and by conductor 81 to line Lconsequent closure of switch 80 completes a circuit for operation ofmotor 16 in a direction to effect opening movement of valve 14, whichcircuit may be traced from line L through the armature 16 of said motor,thence through field 18 and the contacts of switch 80 to line L. Theduration of operation of motor 16 in such direction is dependent uponthe period of joint closure of contacts 53 64 and 10 1| b of theinterrupter switches,which period as aforestated may be varied byadjustment of cams 6!, 62 and 65, 66.

If the single adjustment of valve 14 thus cf.- fected is sufficient tobring the quality of the mixture of fluids in conduit 12 to the valuepreselected by the positioning of pointer 41 the part 31* of needle 31will have been moved to a position overlying the element 12 within thesucceeding period of thirty seconds, so that simultaneous closure ofcontacts 83 '54 and 10 1| will have no effect, due to coincident openingof the auxiliary contacts 12, 12 of switch 12.

If the quality of the mixture in conduit 12 thereafter falls below thevalue preselected by the adjustment of table 45, the value of theelectromotive force generated in the circuit of coil 38 will bedecreased and part 31 of. needle 31 will move toward the left to overlieelement 12 Therefore upon raising of table 45 contactor 12 will betilted into engagement with contact 11", and upon simultaneous closureof the interrupter contacts 53 64 and 10 1| an energizing circuit willbe completed for the winding of switch 19, said circuit extending fromline L through switch 13, interrupter contacts 63 64* contacts 13 13 ofswitch 13, thence through interrupter contacts 10*, 11 and throughauxiliary contacts 12*, 12 and contacts 12, 12 of switch 12, byconductor 88 through the winding of switch 19, and by conductor 81 toline L}. Consequent closure of switch 19 completes a circuit for motor16 to cause closing movement of valve 14, said circuit extending fromline L through the armature of said motor 18, by conductor 89 throughfield 11, and through the contacts of switch 19 to line L If the singleadjustment of. valve 14 thus effected is insufficient to bring thequality of the mixture in conduit 12 to the preselected value, anadditional adjustment of said valve in the same direction will beeffected at the end of the next succeeding period of thirty seconds, asaforedescribed. By the means aforedescribed the valve I4 isautomatically adjusted in the required direction upon either an increaseor decrease in the total heating value per unit volume of the mixtureflowing in conduit I2, whereas if such' value remains unchanged theauxiliary contacts 12, 12 of switch I2 are operative to prevent anyadjustment of said valve. The thermo-couple device herein disclosed isextremely sensitive to variations in the total heating value per unitvolume of the gas sample and the galvanometer is therefore quicklyresponsive to such variations. Hence the provision of means forsimultaneously closing the contacts of both interrupter switches atpredetermined time intervals is desirable merely to prevent huntingofthe control mechanism; but as will be understood such time intervalsmay be varied as desired to suit the requirements of each particularinstallation.

Obviously if. the flame of burner 20 is extinguished for any reason, orif the circuit of coil 36 of the galvanometer is broken, as by failureof the hot-junction or cold-junction of the thermo-couple, the resultingdecrease or failure of current in coil 36 will permit needle 31 to movequite rapidly, under the bias of spring 38, toward its left-handposition. Part 31 of the needle will then overlie element 73B of switchI3, and upon raising of table 05 the contactor 13 will be moved intoengagement with contact 73. At the same time, as aforedescribed, theinterrupter contacts 63 60 will be closed to complete a circuit for thewinding of an electromagnetically operable switch 90, said circuitextending from line L through switch B and interrupter contacts 63, 64conductor 83 to and through contactor 13 and contact I3 of switch I3,conductor 9! through the winding of switch 90, and by conductor 92 toline L I Closure of switch 90 completes a circuit which may be tracedfrom line L through the primary winding 90 of a well known form ofspark-coil, designated in general by the numeral 95, thence through theleft-hand contacts of said switch, and by conductors 96 and 91 to line LThe secondary winding 98 is grounded at one end and the other endthereof is connected by conductor 99 with a spark-plug or spark-gapelement I00 of usual form, which is grounded as indicated at IN. Theintermittent sparking at plug I00 tends to re-ignite the stream of gasat the tip of burner 20, and if extinguishment of the burner flame wasthe sole trouble, the several parts of the control -device will beautomatically returned to the normal positions occupied thereby prior tofailure of the burner. In this connection it should be noted that due tothe relatively quick movement of needle 31 toward its left-hand positionuponfailure of the burner, the contactor 13 is so quickly disengagedfrom contact I3 of switch I3 as to prevent any improper adjustment ofvalve M through closure of switch I9 at such time, inasmuch ascontinuity of the circuit through interrupter contacts 10 II is brokenupon the aforementioned disengagement of contactor 73 from contact 13The quality of the mixture flowing through conduit I2 will therefore notbe substantially affected by temporary failure of the burner 20 or byfailure of the thermo-couple circuit pending correction of the fault, asby substitution of a new hotjunction element.

The right-hand contacts 90 of switch 90 when closed complete acircuit'from battery I02 through a bell-ringer I03 or any other audibleor visual warning or indicating element,-a manually operable switch I04being provided which is adapted to be closed when the operation of thecontrol system as a whole is initiated.

Means are also preferably provided for sounding the alarm bell I03 uponfailure of voltage in the energy supply lines L L said means, as shown,comprising a relay I05 having its winding connected across said lines LL to normally interrupt the circuit through contacts I05 thereof, whichwhen closed provide a circuit shunting the contacts 90 of switch 90.

As will be understood by those skilled in the art, a given increase intemperature of the liquid I5 in tank I6 will result in a known decreasein the total heating value per unit volume of the gas supplied to burner20. This phenomenon is principally explained by the fact that at thehigher temperature an increased amount of water vapor is present in eachunit volume of combustible gas and hence a correspondingly reducednumber of potential heat units will be present in such unit volume. Forinstance the number of heat units in a unit volume of the gas will bedecreased to the extent of approximately two and one-half per cent for atemerature increase of, say, 20 degrees F. at ordinary operatingtemperatures. In order to compensate for such variations in tanktemperature, I prefer to employ a coiled bimetallic thermostatic strip'38 as a support for the hair-spring 38 of the galvanometer. Thecompensation thus effected amounts to approximately two and one-half percent in a 7 rise in tank temperature of, say, 20 degrees F., and hencematerially increases the accuracy of the control system. Stated anotherway, the effect of the bimetallic support 38- is to move the vzeroposition of the needle 31 in accordance with and to compensate forchanges in tank temperature. While the showing herein is diagrammatic itis to be understood that in practice the bimetallic strip will be sopositioned with respect to the liquid in tank I6 as to be definitelysubjected to the variable temperature of the latter.

Any suitable means may be provided for recording the movements orvariations in position of the galvanometer needle 31. Ihave shownherein, by way of example a recording device which is auxiliary tooradditional to the aforedescribed galvanometer parts. Thus I may employ agalvanometer I06 of usual form having a recording pen or element I0! forcooperation with a known form of chart I00 which is movable at aconstant relatively slow speed by the motor I 09, which may be connectedwith any suitable source of energy supply, such as lines L L Thelefthand side of the coil of galvanometer I06 is connected by conductorH0 with the lead wire M of the hot-junction 39 of the thermo-couple, andthe right-hand side of said coil is connected by conductor II I through.a selectable portion H2 of a resistance element I I2, which is notaffected by temperature changes, and through slider H3 and conductor I II to the lead wire 02 of the coldjunction 40 of the thermo-couple,sliderH3 being adjustable to provide for zero positioning of pen I01 when theneedle 31 of the other galvanometer is at the position preselectedtherefor by the setting of pointer 41.

The coil of galvanometer I06 is thus connected in circuit in series withthe hotand cold-junctions of the thermo-couple in substantially the samemanner as coil 30 aforedescribed. In order to compensate for variationsin tank temperature I supply to the circuit including the fixedresistance H2 and an element H5 having a positive temperature-resistancecoefiicient a source of substantially constant voltage. Element H5 is solocated as to be subjected to the variations in temperature of tankliquid I5. Said source may comprise a battery H6, which preferably hasassociated therewith a resistance I I1, said resistance III beingmanually adjustable by means of a contactor II'I to compensate forgradual weakening of the battery. The coil circuit of galvanometer I06as thus connected is subjected to the effect of variations in voltagedrop across the portion H2 of resistance H2, which variations are inturn dueto variations in the resistance value of element H5 as anincident to variations in the temperatureof the tank liquid I5. Theresistance values of elements I I2 and H5 and the value of theelectromotive force supplied from battery H6 will be chosen to give thedesired decrease in electromotive force of two and one-half per cent foreach twenty degrees increase in temperature of liquid I5. The chart I08may be calibrated for direct and continuous indication and recordationof the instantaneous total heating value per unit volume of the fluidflowing in conduit I2; or said chart may be so calibrated as to providean intermediate zero marking corresponding to the total heating valueper unit volume preselected by the setting of pointer 41.aforementioned, with percentage calibrations on each side of the zeromarking, to indicate and record the percentage variations of such totalheating value per unit volume with respect to the value so preselected.

The galvanometer I 06 is provided with the usual hair-spring H8 to biasthe needle I01 to its normal or zero position. From the foregoingdescription it will be apparent that either the mechanical meanscomprising the bimetallic strip for supporting the hair-spring of thegalvanometer, or the electrical means comprising the potentiometerconnection of the circuit containing the temperature responsiveresistance I I5 and the fixed resistance H2 with respect to the coilcircuit of the galvanometer, may be employed to effect the desiredcompensation for variations in temperature of the tank liquid I5,--thetwo arrangements illustrated being substantially equivalent in function.

The mixing control system aforedescribed is extremely sensitive tovariations in the quality or total heating value of the fluid theconstituency of which it is desired to control, and the elements thereofare operable quickly and automatically to vary the rate of flow of oneof the constituents of the mixture to maintain the quality thereofsubstantially constant. In practice it has been found that thisquick-acting mixing control system will automatically maintain the mixedgas within two per cent of the desired or preselected value over fairlylong periods without manual checking. If closer accuracy and continuousautomatic checking are desired a precision calorimeter of the characterdisclosed in the Packard Patent No. 1,625,277, dated April 19, 1927, maybe readily combined with the'aforedescribed control system without inany way interfering with the rapid response and operation of the latter.By employment of a quick-acting mixing control system of the type hereindisclosed in combination with a relatively slower acting precisioncalorimeter of the character disclosed in said Packard patent, automaticmaintenance of the mixed gas at well within one per cent of the desiredoftime, while at the same time eliminating the necessity for any manualoperations or corrections.

Such a combination of elements is illustrated more or lessdiagrammatically in Fig. 3, wherein the quick-acting mixing controlsystem aforedescribed may be used in its entirety. Identical parts havebeen given like characters of reference in Figs. 1 and 3 and certain ofthe circuit connections have been omitted in the latter figure merelyfor simplicity of illustration. The essential difference in thequick-acting control system in Fig. 3 is that instead of controllingenergization of fields 49 and 50 manually (as by means of thepush-button switches 49 50 of Fig. 1), energization thereof is subjectto control automatically as .by means of normally open switches 49 50closure of which is respectively effected by means of cams 49, 50carried by the oscillatable shaft H9, movement of which is controlled ina well known manner in response to variations in the quality or totalheating value per unit volume of the gas mixture flowing in conduit I2,as determined by the relatively slow acting precision calorimeter,designated in general by the numeral I20. Said calorimeter, asaforestated, is preferably of the character disclosed in said PackardPatent No. 1,625,277.

Here as in said Packard Patent No. 1,625,277 the calorimeter I20 hasassociated therewith a Wheatstone bridge circuit, of which theresistances I30 and I 3I form two fixed arms, the inlet and outletthermometer resistances designated by the numerals I32 and I33 formingin conjunction with the balancing resistance or rheostat I34 the othertwo arms of the bridge circuit. Included in circuit in series with thethermometer resistance I32 is a fixed resistance I35 the resistancevalue of which'is equal to that of resistance I34. The purpose of thisresistance I35 is to bring the Wheatstone bridge circuit into balancewhen the contactor I34 is moved in a counterclockwise direction to oneextreme position thereof which corresponds with the left-hand end ofscale I36; or, in other words, when no heat is being imparted to theflow of cooling fluid between thermometer resistances I32 and I33.

The coil I3! is connected across the bridge circuit through the mediumof a variable resistance I 38 whereby the bridge circuit may beinitially balanced. The needle I3! of the galvanometer is cooperablewith ratcheting means of the character disclosed in Leeds Patent No.1,125,699, dated January 19, 1915. The arrangement is such that shaft H9will be oscillated or rotated in one direction or the other upondeflection of the galvanometer needle I 31 to one side or the other ofits neutral position. Said ratcheting means is described in detail inthe aforementioned Leeds patent, but it may be pointed out that the samecomprises essentially a shaft I 39 to be driven unidirectionally at aconstant speed by a motor I40, shaft I39 having spaced cams HI and I42attached thereto for cooperation with members I 43 which arerespectively arranged to drive shaft I I9 (through a friction clutchmechanism) in one direction or the other, depending upon the directionin which needle I 3! has been deflected,it being understood that nomovement of shaft H9 is effected so long as needle I3! remains in itsintermediate or neutral position.

The cams 49, 50 are adjustable upon shaft I I9 to correspond with thepreselected quality or total heating value per unit volume at which itis desired to maintain the mixture of fluids flowing in conduit I2. Thusif it be assumed that the total heating value per unit volume of thefluid in conduit I2 rises slightly above the value preselected thereforby the setting of table 45 and pointer 01 without proper response of theaforedescribed quick-acting mixing control elements, this means that thecalibration of the latter elements is not entirely accurate or has beendisturbed by some means. Accordingly the cam 50 will be movedautomatically in a clockwise direction so that the high portion 50thereof will engage and effect closure of switch contacts 50' Closure ofcontacts 50 will pre-set an energizing circuit for winding 50 to becompleted upon closure of the normally open contacts I2 I, I22 of aninterrupter switch |23,closure of said contacts being effectedperiodically through the medium of adjustable cams I24, I25 carried byshaft 61. Field 50 when thus energized will cause operation of motor 48to properly adjust the table 45 and its associated parts whereby thequick-acting mixing control elements will function more accurately forcontrol of the total heating value per unit volume of the fluid mixturein conduit I2. Y

In a like manner any slight decrease in the total heating value per unitvolume of the gas mixture which is not quickly and accurately correctedby the quick-acting elements will result in movement of cam 49 in acounterclockwise direction to pre-set the circuit of winding 49 forcompletion upon closure of the aforementioned interrupter contacts I2I,I22. Motor 48 will therefore be operated in a reverse direction tocorrect the setting of table 45 and its associated parts.

Shaft H9 is preferably provided with an additional cam I24 which isshaped as illustrated to provide for automatic closure of a pair ofcontacts I25 when the total heating value per unit volume (as determinedby the precision calorimeter I20) increases or decreases to asubstantial degree from the value preselected therefor. Contacts I25 arerespectively connected through conductors I25, I21 (see Figs. 3 and 1)across the circuit, of battery I02 and bell I03 in shunt to the contacts90 of switch 90, whereby the bell will be sounded to warn the attendantof the existing condition.

The precision calorimeter I 20 shown in -Fig. 3 maybe supplied withenergy from any suitable source of direct current. As shown herein,however, it is assumed that lines L L are supplied from a suitablealternating current source. Accordingly suitable means such as thetransformer I28 and rectifier elements I29 are employed to provide aproper current supply for said calorimeter. The other elements ofcalorimeter I20 and the manner of operation thereof are disclosed in theaforementioned Packard patent or are well understood by those skilled inthe art.

I do not claim herein broadly the idea of controlling the constituencyof a mixture of gaseous fluids in accordance with the determinations ofa quick-acting calorimetric device, which calorimetric device is'subjectto monitoring or supervisory control in accordance with thedeterminations of -a relatively slow acting calorimetric device of theprecision type, as that subject matter is disclosed and claimed inPatent No. 1,686,751, issued under date of October 9, 1928 to U. 0.Hutton and myself. I do claim the idea of providing a quick-actingcalorimetric device which in itself is adapted to function accuratelyindependently of, or to compensate for, variations in temperature,pressure and saturation conditions of the fluid mixture being tested;whether said quick-acting calorimetric device is used alone or inconjunction with a relatively slow acting calorimetric device of theprecision type to modify the control characteristics of the former.

What I claim as new and desire to secure by Letters Patent is:

1. The method of regulating the volumetric proportionality of aplurality of flows of gaseous fluids to provide a gaseous mixture ofsubstantially constant total heating value per unit volume whichconsists in effecting a flowing mixture of said fluids, continuouslywithdrawing and buming a volumetrically constant sample of said mixtureto determine the instantaneous total heating value per unit volumethereof, automatically regulating the volumetric proportionality of saidflows of fluids relatively to each other in accordance with thedeterminations so effected, and automatically discontinuing suchregulation and giving an audible signal when'the total heating value perunit volume of said mixture varies to a given degree with respect to apreselected value. i

2. In a quick-acting calorimetric device, in combination, a burner,means for continuously supplying to said burner under like conditions oftemperature, pressure and saturation constant volumetricallyproportioned flows of test gas and air to support combustion of saidtest gas, a galvanometer, a thermo-couple havng hotand coldjunctions, acircuit connecting said galvanometer to said junctions, the hot-junctiononly of said thermo-couple being subjected to the thermal effect ofcombustion of said flows of gas and air whereby an electromotive forceproportional to the total heating value per unit volume of said gas isgenerated in the circuit, and means controlled by said galvanometer fordirectly and continuously indicating the instantaneous total heatingvalue per unit volume of said gas.

3. In a quick acting calorimetric device, in combination, a burner,means for continuously pp ying to said burner under like conditions oftemperature, pressure and saturation constant volumetricallyproportional flows of test gas and combustion air, said means comprisinga pair pf positive displacement pumps, a container, said containerhaving therein a body of liquid within which said pumps are partlysubmerged, a thermo-couple having the cold-junction thereof subjected tothe temperature of said liquid and having the hot-junction thereofsubjected to the temperature of the burning flows of test gasvand air, agalvanometer, a circuit connecting said galvanometer to said junctionswhereby said galvanometer is supphed with an electromotive forcedirectlyproportional to the instantaneous total heating value per unit volume ofsaid test gas, and means controlled by said galvanometer for varying theconstituency of said test gas whereby the total heating value per unitvolume thereof is maintained substantially constant,

4. In a quick acting calorimetric device, in combination, a burner,means for continuously supplying to said burner under like conditions oftemperature, pressure and saturation constant volumetricallyproportioned flows of test gas and combustion air, said means comprisinga pair of positive displacement pumps, 2. container, said containerhaving therein a body of liquid within which said pumps are partlysubmerged, a thermo-couple having the cold-junction thereof subjected tothe temperature of said liquid and generated in having the hot-junctionthereof subjected to the temperature of the burning flows of test gasand air, a galvanometer, a circuit connecting said galvanometer to saidjunctions whereby said galvanometer is supplied with an electromotiveforce directly proportional to the instantaneous total heating value perunit volume of said test gas, means controlled by said galvanometer forvarying the constituency of said test gas whereby the total heatingvalue per unit volume thereof is maintained substantially constant, andthermally responsive means operatively associated .with saidgalvanometer and subjected'to a temperature substantially correspondingto the temperature of said liquid, said means being adapted to modifythe controlling effect of said galvanometer in accordance with and tocompensate for variations in the temperature of said liquid with respectto a given value.

5. In a gas mixing control system, in combinameans for efiecting amixture of said gaseous fluids, a quick-acting calorimetric deviceincluding a burner, means to supply to the burner constantlyproportioned volumes of the aforementioned gaseous mixture andcombustion air under like conditions of temperature, pressure andsaturation, a thermo-couple arranged to be subjected to the calorificefiect of the combustion, a galvanometer, and a circuit connecting saidgalvanometer to said thermo-couple whereby the former is subjected toeter, said element being arranged and calibrated in a manner toaccurately compensate for variations in the apparent total heating valueper unit volume of the gaseous mixture supplied to the burner as anincident to variations in temperature of said mixture prior to burningof the latter.

of said gaseous fluids, a quick-acting calorimetric device including aburner, means to supply to the burner constantly proportioned volumes'of the aforementioned gaseous mixture and combustion air under likeconditions of temperature, pressure and saturation, a thermo-couplearranged to be subjected to the calorific effect of the combustion, agalvanometer, a circuit connecting said galvanometer to saidthermo-couple whereby the former is subjected to the electromotive forcethe latter, means including a poweroperated valve controlled by saidgalvanometer for varying the proportionality or" said flows of fluids inaccordance with and to compensate for variations in the total heatingvalue per unit volume of said mixture with respect to a preselectedvalue, and associated means for modifying the controlling eifect of saidgalvanometer to compensate for possible error in the determinations ofsaid quick-acting calorimetric device, said means comprising aslow-acting calorimetric device of the precision type, saidlast-mentioned calorimetric device being also'adapted to burn acontinuous sample of said gaseous mixture.

nation with means 7. In a gas mixing control system, in combination,means providing a plurality of flows of gaseous fluids, power-drivenmeans operable automatically to vary the proportionality of said flowsof fluids whereby a flowing mixture of said fluids of substantiallyconstant total heating value per unit volume is provided, and controlmeans for said power-driven means, said control means including aplurality of circuit interrupting elements respectively operated atunlike speeds and tending jointly to efiect periodic operations of saidpower driven means, certain of said interrupting elements being adaptedto function individually under given conditions for the performance ofother controlling functions.

8. In a gas mixing control system, in combination, means providing aplurality of flows of gaseous fluids of unlike total-heating value perunitvolume, means for proportioning said flows to provide a gaseousmixture of substantially constant preselected total heating value perunit volume, said means comprising a calorimetric device having aburner, means to supply to the burner constantly proportioned volumes ofthe gaseous mixture and combustion air, a thermocouple arranged to besubjected to the calorific effect of the combustion, a galvanometer, acircuit connecting said galvanometer to such thermo-couple whereby theformer is subjected to the electromotive force generated in the latter,means controlled by said galvanometer for indicating the instantaneoustotal heating value per unit volume of said mixture, and means formodifying the operation of said galvanometer in accordance with and tocompensate for variations in the apparent total heating value per unitvolume of the mixture supplied to the burner as an incident tovariations in the temperature thereof, said means comprising an elementhaving a positive temperature-resistance coeflicient to be subjected tosuch temperature variations, a second element having a fixed resistancevalue, a source of electrical energy of substantially constantpotential, means for connecting said elements in series with each otherand in circuit with said source, and additional circuit connectionswhereby said galvanometer is subjected to variations in the potentialdrop across a portion of said second-mentioned element.

9. In a gas mixing control system, the combiproviding a plurality offlows of gaseous fluids of unlike total heating value per unit volume,of means for effecting a mixture of said fluids, calorimetric means,including a burner, for withdrawing and burning a continuous sample ofsaid mixture to ascertain the instantaneous total heating value per unitvolume of the latter, means including an electrically operatedvalvesubject to control by said calorimetric means and operable automaticallyin response to variations in the ascertained value with respect to apreselected value for varying the volumetric proportionality of saidflows of fluids whereby the total heating value per unit volume of themixture is maintained substantially constant, means including anelectromagnetically operable relay associated with said calorimetricmeans and adapted to be energized by the latter only upon extinguishmentof the burner flame, and means associated with said relay and operableupon energization of the latter to provide for re-ignition of the sampleof said mixture.

EDWIN X. SCHMIDT.

